Frequently Asked Questions

Data Communication


Data Communication

Data protocols, transmission or retrieval

Can I use RS-485 transmission?

Yes, instruments can be configured to transmit real-time using full-duplex RS-485.  On RBRvirtuoso, RBRduo and RBRconcerto instruments, the logger needs to have the appropriate external battery endcap (either USB, RS-232 or RS-485) for the required external communication mode, as the wiring differs between the options.  Ruskin is then used to configure the instrument with the appropriate streaming data serial option.  For RS-485 communication, you will also need an RS-485 converter at the receive end.

Is it possible to read real-time data from my logger?

An external waterproof connection can be fitted to most RBR data loggers as an optional extra at the time of manufacture.

My logger doesn’t communicate
First, verify that you have a connection through the com port on your computer.
Ruskin automatically connects to the logger by searching for the COM port the CPU has assigned to the USB port. This process may take a few seconds, so please wait at least 30 s to one minute to ensure that Ruskin has found the logger.
When the logger is found it is displayed in the Navigator Pane. You can click on the Instruments heading (Navigator pane) and see all the serial Ports on the Local Server Tab. If your logger is not listed there and the table indicates COM X –> “Transport Enabled” then there is a communication problem. If the logger is listed then Ruskin has found the logger and is communicating with it.

Still can’t communicate?

  • Make you are using the correct download cable for your instruments, and check to make sure it is not damaged or faulty.  If possible, try the cable with another RBR instrument to see if a connection can be established.
  • Make sure the USB drivers are installed on your computer (particularly if you have not used Ruskin previously).  In Ruskin, click on Instruments -> Install logger USB driver.  If the drivers are installed, Ruskin will display a message confirming this.
  • Reset the logger – unplug the instrument from your computer, remove the batteries, wait for approximately five minutes, and then re-install the batteries.  Retry connecting to Ruskin.
  • For legacy instruments (such as XR, TDR, TR, etc.), replace the batteries with fresh cells, as they require an internal power supply in order to communicate.

What communications options are available?

All current RBR instruments support USB as standard. In the Compact Logger family (RBRsolo, RBRduet) the micro USB connector is used internally, whereas for the Standard Logger family (RBRvirtuoso, RBRduo, RBRconcerto, RBRmaestro) the 30 pin Apple connector is used. Cables for both these connectors are available globally from any consumer electronics source, in case you need to replace the cable supplied with the instrument.

In addition, RS-232 and RS-485 serial connections are available on the Standard Logger family. In fact, the 30 pin connector contains pins for not only USB but also the serial connection simultaneously. The most convenient way of accessing the serial lines is to change the battery end cap (BEC) as there are variants wired for external USB, RS-232, and RS-485 (full duplex) all available.

Our legacy instruments (1060/1050/2050/XR families) all have RS-232 connections, using either an RJ-11 telephone jack connector or a mini-USB connector and a proprietary cable as the pins are actually serial, not USB. For many computers, a serial-to-USB converter is required. RBR recommends EasySYNC ES-U-1001-A or any other adapter based on an FTDI chipset.

RS-232 details
Only TX,RX, and GND lines are used for RBR instruments – no hardware handshaking lines are required.

RS-485 details
RBR instruments support full duplex RS-485, requiring A+,A-,B+,B-, and a GND line. We recommend the use of twisted shielded pair cable for any significant distance, and drawings are available if you wish to assemble your own cable. Cables are also available from RBR directly.

Serial in general
Modern RBR instruments default to 115200 baud when shipped from the factory, unless custom requests have been made. This setting can be changed using our Ruskin software, both over a serial connection or a USB connection.

What is the maximum cable length for serial RS-232 transmission?

RBR uses generic RS-232 protocol. The maximum length depends on the quality of the cable used and the baud rate but we have had success over greater than 200m at 9600 baud


Internal and external power.


Internal and external power

Is it possible to use external power with my logger?

Instruments with an external data connection, such as RS-232 or RS-485 (FD) include the option of externally powering the instrument.


Choose the right sensor.


Choosing the right sensor for your application

What is the best pressure transducer for my application?

At the time of manufacture, we can use any one of the following options for the depth channel:

  • For the plastic case, select from  0 to 20, 50,100, 200, 500, or 1000 (all in metres of water).  Please note the plastic housing itself has a maximum pressure range of 740m, so even though a 1000m transducer may be selected, the maximum depth of deployment will be 740m to avoid breaching the housing.
  • For the titanium case, select from 0 to 1000, 2000, 4000, 6000 or 10,000 metres

These are all nominal full scale ranges, and the accuracy of the pressure measurement will be 0.05% of this full scale range.   For example,  if you have a full scale of 500 metres, the accuracy of the pressure measurement is 0.05*500/100 or 0.25m.

The selection is complicated by another factor: each range has a maximum beyond which it should not be used.  This is called the “proof pressure”, and it is the range up to which the pressure sensor can be deployed without causing permanent damage to the transducer.  Between the full scale pressure and the proof pressure, the sensor may or may not function properly, but once the  instrument returns to a depth shallower than the full scale range, normal operation will resume.

Full Scale Range (m) Absolute Maximum Pressure (m)
20 40
50 70
100 150
200 300
500 740 (limited by  housing)
1000 (plastic) 740 (limited by housing)
1000 (titanium) 2000
2000 3000
4000 6000
6000 9000
10000 11000



What is the difference between Turbidity and OBS and TSS?

Sometimes there are different terms which mean the same thing. Turbidity is a quantity measured by optical back-scatter of light and OBS stands for Optical Back-Scatter. TSS or Total Suspended Solids is also a quantity measured using optical back scattering.

Turbidity and TSS are essentially the same parameter. Although turbidity purports to measure approximately the same water quality property as TSS, the latter is more useful because it provides an actual weight of the particulate material present in the sample. The relationship between turbidity and TSS (total suspended solids) depends on the nature of the solids, but all turbidity sensors measure optical back scatter.

Here is the description from the Seapoint site:

“The Seapoint Turbidity Meter is a very low-power, miniature sensor that detects light scattered by particles suspended in water, generating an output voltage proportional to turbidity or suspended solids.”

And here is the description from the D&A site:

“The OBS®-3+ sensor measures suspended solids and turbidity by the optical back-scatter method (ASTM 6677). It features a compact micro probe that responses almost linearly over a 1000-fold change in sediment concentration (SSC) and turbidity.”

It amounts to exactly the same thing. The responsibility for calibration from turbidity to TSS in either case rests with the user.

When should I use a DO Optode sensor rather than a galvanic DO sensor (Oxyguard)?

It depends on your application and budget. Both the galvanic cell sensor and the optode sensor are accurate instruments. The optode is more expensive than the galvanic cell sensor, but long term can be more stable, and does not require periodic refurbishment and recalibration.  The Oxyguard has a lower initial cost, but does require periodic refurbishment and recalibration by the end user to ensure it is accurate measurements.  Normally for short duration deployments we recommend the galvanic sensor, but for deeper and longer deployments, we recommend the optode.

You offer two types of depth gauges – how do I choose one over the other?

Yes we offer two types, one is a strain gauge and the other is a quartz crystal. The strain gauge is what we recommend for most applications as it has an accuracy of 0.05% full scale accuracy, while the quartz sensor has an accuracy of 0.01% full scale. So depending on the accuracy of the depth you need the choice should be based on these characteristics.

You offer two types of DO sensor and two types of fluorometers. Why and what is the difference between them?

When we can we try to offer sensors in different price and accuracy categories or for special purposes.

In the case of the DO sensors we offer a Galvanic cell sensor and an Optode. The galvanic cell sensor is less expensive than the optode but requires more routine maintenance to keep it operating effectively.

With regard to the fluorometers, our standard offering is either the Turner Cyclops-7 and the Seapoint fluorometer. The selection depends on the depth rating required 6000m or 600m and the range (µg/l) of the measurement (up to 150 µg/l or 500 µg/l), as well as pricing and power requirements.  The Turner sensor is a less expensive sensor, but does have higher power requirements which would limit possible deployment life for deployments without external power supply to the instrument.


 Logger differences and configurations.

Logger Availability

Configuration options and their availability

Can you make multi-channel loggers with configurations that are not on your list?

RBR prides itself on the flexibility of its products.  While not all configurations are possible due to mechanical or electronic requirements, we are happy to review any sensor requirements to determine feasibility.


Ruskin, its predecessors, and more.


RBR Ruskin Software and its predecessors

How can I update my firmware?

The firmware on our latest generation of instruments (RBRvirtuoso/duo/concerto/maestro, RBRsolo/duet) is field upgradable through our Ruskin software.  If you are running Ruskin on a computer connected to the internet, and plug in a logger, Ruskin will automatically check if a new firmware version is available, and will ask you if you would like to upgrade your logger.  You can also manually upgrade the firmware in Ruskin, under the Instruments menu, select Upgrade logger firmware.

Firmware updates for legacy instruments such as the XR series or TDR instruments may not be possible depending on the age of the instrument.  If the firmware can be updated, it will require the instrument to be returned to the factory, and the upgrade would be a chargeable service item.